v did the isolationist actions of the US affect lasting peace in Europe after World War I' Without US support, the League of Nations weakened significantly Without US help, European nations could not prevent use of military force. Without US help, secret military alliances no longer took place. Without US support, European countries did not ratily the Treaty of Versailles.

The isolationist actions of the US after World War I had a significant impact on the lasting peace in Europe. Without US support, the League of Nations weakened significantly, which made it difficult for European nations to prevent the use of military force. This lack of enforcement power allowed for the rise of aggressive regimes and the outbreak of World War II. Additionally, without US help, European countries did not ratify the Treaty of Versailles, which further destabilized the region. Overall, the isolationist actions of the US contributed to the lack of lasting peace in Europe after World War I.